Resectoscopes are medical devices useful for the resection of biological tissue, usually in order to remove pathologies in the tissue or to sample suspect tissue. Resectoscopes are elongated, narrow devices, which penetrate mammalian cavities. Typically, the resectoscope's distal end is positioned in the cavity and its proximal end is located outside the body. Resectoscopes comprise inter alia an elongated optical system and an actuator, wherein the actuator has means to translate a movement of at least one handle along the longitudinal axis of the resectoscope to the movement of a resecting loop, wherein the loop is connected to an electrical source and thus has means to resect the desired tissue along the longitudinal axis.
All resectoscopes known in the art comprise a cutting member, wherein cutting is enabled by means of an electrical current, which produces sufficient heat to coagulate and cut tissue. The heat burns the resected tissues so further analysis of the tissue is impaired.
The user of resectoscopes known in the art determines the depth of cutting beneath the tissue mucosa. The more the user presses the resectoscope against the tissue, the deeper the resection. However, resection using motion along the longitudinal axis provides no reference to guide the user as to the necessary depth of resection. Resection therefore often depends mainly on the user's sensitivity, experience and technical skills. In order to avoid penetration of organs and contamination of the body with diseased tissue, thereby introducing complications to the surgical procedure, users avoid pressing the resectoscope. Most procedures therefore yield inefficient resection depth and therefore inaccurate pathological staging. Moreover, due to technical characteristics of the aforementioned endoscopic resection, specimens are often found excessively cauterized and inappropriate for accurate pathological diagnosis. Likewise, technical disadvantages of the aforementioned endoscopic resection prevent the complete removal of the tumor tissue. Herr et al. demonstrated that up to 76% of the patients with bladder tumors have residual tumors after an initial resection, and 30% of the patients were inaccurately downstaged at initial trans-urethral resection. They therefore advocate routine repeat resection for every patient to control noninvasive tumors and to detect residual tumor invasion (J. Urol. July 1999; 1 62(1): 74-6).
Prior art resectoscopes, their method of use, and ancillary systems usable with them are discussed in PCT application WO 0172200, filed Mar. 29, 2001, assigned to the present applicant and incorporated herein by reference in its entirety.